Rubber footwear



0.1. RANDALL.

RUBBER FOOTWEAR.

APPLICATION FILED IAN. 4. 1918.

1,818,593. Patented 001.1411919.

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UNITED lSTATE-s PATENT oEEIoE.

CHESTER J'. RANDALL, 0F NAUG'ATUCK, CONNECTICUT, ASSIGNOR TO THE GOODYEARS METALLIC RUBABER SHOE COMPANY, A CORPORATION OF CONNECTICUT.

y RUBBER FOOTWEAR.

Specication of Letters Patent.

Patented Oct. 14, 1919.

. To all whom z't may concern.'

Be it known that I, CHESTER J. RANDALL, a citizen of the United States, residing at Naugatuck, county of New Haven, and State of Connecticut, have inventedv certain new and useful Improvements in Rubber Footwear, of which the following is a full, clear, and exact description.

This invention relates to boots and shoes made by rubber footwear methods and more particularly to .boots and shoes of this type having soles provided with metallic wearresisting members.

The principal object of the invention is to provide such an article of footwear wherein lthe wear-resisting properties of the shoe may be maintained without disturbing its Water-proof feature or shortening its life of usefulness.

Referring to the drawings forming a part of this specification;

Figure 1 is a plan view of the bottom of a boot embodying the invention, and

Fig. 2 is a sectional view through the line 2-2 of Fig. l.

It is a well recognized fact that leather boots intended for rough wear such as lumbermens boots are materially improved as far as wearing properties are concerned by providing the tread portion of the sole'with protruding nails, studs, or the like, .which relieve the leather surface from much of the wear that it would otherwise be subjected to. Such metallic members have met with favor in leather footwear mainly because the heavy thick leather soles such as are used upon lumbermens boots are very rigid, hard and nonyielding or strain-resisting. For this reason the nails, studs, or the like can be driven through the thick leather and will be firmly maintained in place and gradually wear down with the sole without being loosened or displaced.

Such wear-resisting devices have also been used in rubber footwear of the usual construction, but have not met with success.

The soles of this class of footwear are comparatively soft, yieldin under strainl and elastic. The numerous oles necessary for the introduction of the nails or studs materially weaken the sole, and as it flexes during walking the holes tend to elongate, stretch, and nally become permanently enlarged, so that the studs no longer form a tight t within the receiving holes but become wabbly, loose, and soon fallout or else tear *the rubber about the holes, thereby shortening the life of the boot. This is enhanced by the continual strains put upon the nails from all directions from the harsh use to which the boots of this type are put. Moreover the loosening of the studs or their actual falling out results in producing a leaky structure so that the boot is of no further use as a water-proof article.

Ina water-proofboot or a boot that is 'made by rubber factory methods all the parts are assembled together upon a last by the aid of rubber cement while the vulcanizable rubber components are in an unvulcanized state, and when the assemblage of the parts is completed the entire structure lis placed within a vulcanizer and vulcanized, thereby producing a leak-proof vulcanized unitary boot. It is not feasible to incorporate a leather sole into the boot during the building up process onthe last for the degree of heat necessary for the subsequent vulcanization would ordinarily result in the utter destruction of the leather composing the sole.

I have discovered that the advantages of the studded leather sole may be maintained and the disadvantages of the studded rubber sole avoided by the use of a vulcanizable rubber sole which has none of the undesirable properties of such a sole but possesses the desirable properties of the leather sole. That is to say I have found that the soft, yielding, elastic properties of the rubber may be avoided and the hard, rigid, non-elastic properties of the leather attained by incorporating with the vulcanizable rubber compound a suitable amount of substantially non-elastic, or strain-resisting fibrous material, such for instance as ten t0 fifteen per cent. of cotton fiber. This composition will withstand the degree of heat necessary to produce vulcanization and will present a Stiff, hard, inextensible structure with which the studs, nails, or the like may be associated without the danger of their becoming loose, Wabbly, or tearing the rubber thereby shortening the life of the boot and destroying its leak-proof properties.

buch a stiff composition, however does not readily flow under the vulcanizing heat and therefore does not vulcanize to make a strong bond with the usual grade of vulcanizable stock Yused in the boot upper or parts to which the sole must be secured. I have therefore found it essential to further provide an intermediate stratum or layer of relatively high grade rubber which is soft and yielding and will readily flow under the vulcanizing heat and thereby weld itself to both the stiff sole and relatively poor compound of the upper. I The vulcanizing process will thus strongly bond all the parts together into 'a unitary and strong structure. The layer of high grade rubber furthermore forms a seal for the heads of the studs, thereby preventing any possible leakage that might otherwise occur from water working up the sides of the studs and entering the interior of the boot through the fabric parts or crevices in the'rag filler.

The boot shown in the drawing is simply a conventional type and is for illustrative purposes only, as my invention may be used with various types of boots and shoes of the water-proof type, and in fact the advantages may be employed wherever a sole of vucanized rubber provided with studs, nails, or the like is desired to be used.

The boot in the present illustration comprises the insole 1 and the boot upper which is composed of the lining 2 and the rulbber outer covering 3. These are built upon a last in the usual way, the lower margin of the, rubber covered upper being turned in below the insole, the rag stock filler sole 4 being shown in this particular instance below the inner sole 1, and in direct contact along its outer margins with the inturned upper.

The out-sole 5 is formed of any suitable rubber compound which has incorporated with it, preferably during the milling of the compound, a quantity of fibrous material, as for instance from five to ten per cent. of cotton fiber. This stock is usually sheeted or calender rolls and then plied up to the required thickness. The holes 6 are then punched in the green plied-up structure and the nails 7 forc'ed therethrough and sufficient pressure applied to force the heads 8 into the rubber stock to make a fiush joint with its upper surface.

A sole of this composition while readily ties, as before mentioned, to strongly unite with the shoe upper to make a perfectly water-tight union, and a union of sufficient strength to withstand the strains put upon the boot when in service. I therefore apply a layer of substantially pure rubber 9, with the necessary vulcanizing ingredient incorporated therein, to the upper surface of the sole. This serves as a bonding medium between the sole and upper and further acts as a seal for the studs preventing any water working into the boot. The boot is then placed in the vulcanizer and the entire structure vulcanized by a single operation to produce a strong, unitary integral structure.

While in the preferred embodiment of my invention I incorporate the strain-resisting material throughout the rubber mass preferably during the milling of the compound, I may however, interpose layers of fibrous material such as woven fabric between the layers of sheeted rubberwhich are used in building up the sole. Or I may when desired localize the strain-resisting component of the sole relative to the spaces between the respective nail holes in a manner to prevent thestretching of the sole with a resultant destructive loosening or falling out of the nails or studs.

It is obvious that other modifications may be made to attain the result desired without departing from the spirit of my invention, and I do not wish it to be understood as limiting myself to the specific embodiment herein shown except as indicated in the appended claims.

Having thus described my invention, what I claim and desire to protect by Letter Patent is:

1. In a waterproof boot or shoe of vulcanized rubber compound and fibrous material, the combination of an insole, a rubber covered upper having its lower margin turned inwardly below the insole, an outsole formed of rubber compound having ground fiber incorporated throughout its mass rendering the same relatively stiff' and ineXtensible, a layer of rubber having higher adhesive qualities than the outsole directly united to said outsole and upper, and numerous nails eX- tending entirely through said outsole and distributed throughout its tread and having their heads sealed between said outsole and layer of rubber, the several parts of said boot or shoe being vulcanized together to form a unitary integral whole.

2. In a waterproof boot or shoe of vulcanized rubber compound and fibrous material, the combination of an insole, a rubber covered upper having its lower margin t turned inwardly below the insole, an outsole vulcanizable has insufiicient owing proper formed of rubber compound having ground fiber incorporated throughout its mass ren'- dering the same relatively stiff. and inextensible, a la er of rubber' having higher adhesive quahties than the outsole directly 5 united to said outsole and the opposed surface, and numerous nails extending entirely through said outsole and distributed about Aits tread and having their heads sealed between said outsole and layer of rubber, the severa-l parts of said boot or shoe being vulcanizedl together toform a unitary whole. Signed at Naugatuck, Connecticut, this 17th day of December, 1917.

. CHESTER J. RANDALL. 

